The conventional vertical blind system includes a single length elongate track having a series of vertical blind vane carrier supports axially translatable within the track. The carrier supports each support a single vane and have the capability to slide in one direction, compressing the carriers and vanes, and also to enable the vanes to rotate about their vertical axis to control the light entering the room. This conventional system will usually have a pair of rope or chain actuators at the end, with one rope actuator for movement of the supports to a first bunched position where the vertical blind is "open" and to a second distributed position where the vertical blind is closed. The second chain or rope actuator operates a vane angle control rod to cause the vertical blind individual units to pivot, preferably about their center, to admit or deny light to the room.
In larger applications, the supporting tracks can be quite long, and although anchoring the track along its length presents no special problems, the vane carriers can experience friction and stress from too large of an operation. As the vertical blind is closed, severe tension builds in the chain or rope actuator. Further, the actuator for pivotal rotation of the vanes will similarly experience an increase in tension by solely shouldering the stress from the force necessary to rotate all of the vertical blind units.
Conventional vertical blind systems are set up for a single expansive spread across a single panel. The vertical panels and their carriers are set for a spaced relationship, but forming closure depends upon each of the spacing members allowing each of the vertical units to reach their exact spacing. At the end of the closure travel, any spacing member which has not enabled a full spaced relationship can hold the end carrier back. Since the blinds are usually high up and operated by wand, the user does not have high positive mechanical advantage which would always allow a good closing force.
Even where the force can be applied, the end carrier may not remain at its terminal position and may move away from full closure. This characteristic makes vertical blinds less than an optimum choice for audio visual rooms where the outside light needs to be completely blocked out. One technique involves the provision of up to a 0.5 inch overlap as a sum of overlap with respect to all of the carriers so that there will be adequate coverage. As the overlap increases, even a full closure can result in a noticeable uneven spacing of the individual vertical blind units.
Even where no sticking occurs, the user can bounce the end carrier against the end of the rail causing it to bounce back. Even at best, the user is required to "fuss" with the vertical blind unit to get it to close completely.
These problems just mentioned are bad enough for single panels having a single one directional coverage, and illustrate why workable two direction coverage is practically impossible. Two direction coverage, where the blinds close toward each other at the center of a panel, would require that the two end carriers meet and remain together. The problems are exacerbated where the bringing of one carrier to another would result in the second carrier being bumped away. The user would have to manipulate two control wands together placing a bending force on them. The two carriers, even if brought together would be urged apart by the swinging vertical blind units which are suspended from them.
For longer window spaces, conventional vertical blinds are provided in shorter sections. Conventional vertical blind sets are provided as a series of short sections which all close in one direction. A long run of single extrusion has not been possible for several reasons, including: (1) the rotation rod would sag, and (2) specialized end plate structures would be necessary to end closure by one lead carrier and to start another section. A longer single run would be desirable where the user could change configurations more easily.
Vertical blinds are popular due to the increased flexibility in control they offer over drapes, which have a single control to open or closed. However, in some instances, it would be desirable to subdivide a vertical blind over a long track run to enable selected portions of the extent of the run to be independently opened and closed, and the vanes in each section to be independently actuated to an open or closed position.
This presents a problem for the rope or chain control. If multiple controls are provided at the end of a track, the cross sectional area of demand for control structures increases and the newer tracks of smaller cross sectional area would be unable to handle the structural demands of multiple controls at the end. In addition, such "remote" control of a far section would include the increased tension and stress which is sought to be avoided in a long vertical blind run.
If the elongate run of vertical blind were simply replaced by several short runs of tracking and controls, several sets of rope and chain controls would extend down along the extended run. This would detract from the aesthetic of the window covering arrangement, and the space between any two short runs would be punctuated by a dangling rope and chain control. Even where the rope and chain control were located at opposite ends, there would be a problem in handling its resting position. If the resting position was on the side of the vertical blinds facing the room, the aesthetic would be ruined as the rope would be exposed. If the resting position was on the side of the vertical blinds facing the window and hidden from the room, a user would have to guess the location, plunging his hands into the vertical spaces between the vertical blinds multiple times to try to find the controls, more "fuss". This would cause frustration and probably some destruction of the vertical blinds where users cannot locate the controls quickly.
In addition, rope and chain controls are being increasingly criticized for their danger to small children. Small children have been known to accidentally hang themselves in the downwardly looping rope and chain controls. Thus, the less rope and chain actuators present, the better for safety. Change their supports at support and track systems for vertical blinds and roller shades have concentrated on two problems with two different structures.
One solution has been to provide a tensioning device at the base of the control to discourage slightly the ability of the child to become entangled with the chain or rope control. These "hold downs" staked at intervals along an extended run would certainly ruin the aesthetic when the blinds were open.
Other vertical blind sets use a single wand control. In this configuration, the lead carrier is fitted with a wand which will be manually grasped to pull the lead carrier to an open position or to a closed position. In addition the wand is linked to the lead carrier such that it is rotated to actuate gears in the lead carrier to turn a control rod to thus actuate all of the carriers to cause individual vertical blind vanes to pivot about their vertical axes.
The single wand control has been used with success on single run vertical blind systems. But the single wand control experiences significant tension and wear, especially where the vertical blind extends over a long length. Usually the wand is connected to the lead carrier with a semi-universal double hook link, and thus either pulling actuation or turning actuation might be accomplished at a high stress position.
In a single wand pull vertical blind system, some accommodation needed to be made for providing complete window closure. This has been typically done by providing several inches, up to about a foot of additional vertical blind tracking and system length beyond the end of the vertical blind run, and providing the wall will enable such additional run due to wall space considerations. This is especially needed where the vertical blind system will stick in places over time and where the user has difficulty in getting the vertical blind system to close completely, or where the system can be brought to a complete close, but rolls open slightly when manually released.
In the single length of vertical blind, lacking independent control, a user on one end would have to walk the length of the system in order to adjust the full length of the system. If the vane control happened not to be nearby, the user has to hunt for it. It would be desirable for a user to be able to actuate a singly controlled vertical blind unit from either end.
Another problem in multi-section vertical blinds is the division of control. Aside from the problem of having a single control rod sagging within the extrusion, the single control rod prevents independent vane control over sections of the vertical blind. Independent control would require even more support where the control rods must begin and terminate at a position other than the ends of the extrusion.
What is therefore needed is a manner of forming positive closure in order that vertical blinds may be closed securely, exactly and precisely with regularity. The closure mechanism should be highly integratable with existing track systems and vertical blind carriers. The system should provide for a distributed system of support which will support any tendency of the rotation rod to sag. The system should provide positive feedback to the operator that the blinds are securely closed. The needed system will provide center opening closure which is positive and which consistently and with assurance seals out light from coming in between the closure points. The needed system would provide adequate closure between adjacent multiple sections of a long vertical blind run, regardless of whether the closing carrier were closing against another lead carrier, or against an end carrier.
The needed system should also provide additional control options, including independent vane angle control over sections of the vertical blind system, as well as multiple controls for the minimum size of controlled section, regardless of whether the minimum size of controlled section is the entire run of vertical blind or an individual section within the complete run. A run generally refers to a single length of extrusion, possibly having a pair of end caps.